JP4623521B2 - Current consumption measuring device - Google Patents

Description

  The present invention relates to a current consumption measuring device that measures current consumption in an analog element in a circuit.

Conventionally, measurement of current consumption in analog elements has been performed in various scenes (see, for example, Patent Document 1). In particular, in an audio device or the like mounted on a vehicle, it is important to measure current consumption of a speaker or the like in order to prevent so-called battery exhaustion.
JP 58-200170 A

  However, in the measurement of current consumption in the conventional analog element, it is necessary to separately use a current detection IC, an OP amplifier and an A / D converter. Since these are connected to the circuit, the apparatus configuration is increased in size. There was a problem of incurring an increase in costs. In addition, there is a problem that a measurement error occurs due to the accuracy of components such as an OP amplifier and an A / D converter used for current consumption measurement.

  An object of the present invention is to solve the above-described problems, and to provide a consumption current measuring device capable of measuring consumption current in an analog element in a circuit easily and accurately.

The consumption current measuring device of the present invention is a consumption current measuring device configured by a digital signal processor and a microcomputer built in a circuit and measuring consumption current in an analog element in the circuit, wherein the digital signal processor is Sampling means for sampling a digital signal representing the voltage level of the analog signal flowing through the circuit at a predetermined period; and an average value for calculating an average value of sampling data of the digital signal obtained by the sampling within a predetermined period Calculating means, and the microcomputer calculates an effective value of a voltage level of the analog signal flowing through the circuit based on an average value of sampling data of the digital signal, and the analog signal. Based on the effective value of the voltage level And having a current consumption estimating means for estimating a current consumption value in the analog device.

According to this configuration, the current consumption in the analog element can be measured using a digital signal processor and a microcomputer that are built in in advance for digital processing of signals in an audio device or the like. In general, digital signal processors used in audio devices and the like can perform high-speed processing, whereas microprocessors often cannot perform high-speed processing as much as digital signal processors. The digital signal representing the voltage level is sampled at a predetermined cycle, the average value of the sampling data of the digital signal representing the voltage level of the analog signal obtained by sampling within the predetermined period is calculated, and the microcomputer calculates the analog signal. Calculates the effective value of the analog signal voltage level based on the average value of the sampling data of the digital signal representing the voltage level , and further estimates the current consumption in the analog element, eliminating the difference in processing speed. And accurate consumption It is possible to measure the flow. Furthermore, unlike the prior art, measurement errors do not occur due to the accuracy of components such as an OP amplifier and an A / D converter used for current consumption measurement.

Further, the current consumption measuring device of the present invention is characterized in that the digital signal processor includes storage means constituted by a number of storage areas corresponding to the number of sampling data of the digital signal obtained by sampling within the predetermined period. And the sampling means sequentially stores the sampling data of the digital signal obtained by the sampling in each of the areas, and the average value calculating means has the storage means in a cycle corresponding to the predetermined period. The sampling data of the digital signal obtained by the sampling may be read from all the storage areas that constitute.

With this configuration, it is possible to easily perform sampling of a digital signal representing the voltage level of an analog signal and calculation of an average value thereof in the digital signal processor.

Further, in the current consumption measuring device according to the present invention, the average value calculating means performs full-wave rectification on the analog signal represented by the digital signal with respect to the sampling data of the digital signal obtained by sampling within the predetermined period. Further, an average value of the sampling data of the digital signal may be calculated by performing a process corresponding to the process of integrating.

  Further, the current consumption measuring device according to the present invention is configured such that when the microcomputer has another element between the analog element and the sampling position of the sampling means in the circuit, You may have a correction | amendment means which correct | amends the consumption current value in the said analog element estimated by the said consumption current estimation means according to the change of a voltage.

  According to this configuration, when there is another element between the sampling position and the analog element, more accurate current consumption can be measured in consideration of a change in voltage due to the other element. Can do.

  In the consumption current measuring apparatus according to the present invention, the microcomputer may include addition means for adding a predetermined idle current value to the consumption current value in the analog element estimated by the consumption current estimation means. Good.

  According to this configuration, when there is an idle current, the current consumption can be measured more accurately by adding the idle current value to the current consumption value.

  According to the present invention, current consumption in an analog element can be accurately measured using a digital signal processor and a microcomputer built in an audio apparatus or the like in advance.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an in-vehicle audio apparatus according to an embodiment of the present invention. An in-vehicle audio apparatus 10-1 shown in FIG. 1 receives a digital audio signal from a network 200 installed in a vehicle and performs audio reproduction. The in-vehicle audio apparatus 10-1 includes a receiver 12, a digital signal processor (DSP) 14, a D / A converter (DAC) 16, an amplifier (AMP) 18, a speaker 20, and a microcomputer 22.

  The receiver 12 receives a digital audio signal transmitted over the network 200 and outputs it to the DSP 14. The DSP 14 performs various processes on the input digital audio signal, outputs it to the DAC 16, and performs a process for measuring current consumption in the speaker 20. The DAC 16 converts the digital audio signal processed by the DSP 14 into an analog audio signal and outputs the analog audio signal to the AMP 18. The AMP 18 amplifies the input analog audio signal with a predetermined amplification degree and outputs the amplified signal to the speaker 20. The speaker 20 outputs a sound corresponding to the amplified analog audio signal. The microcomputer 22 performs processing for measuring current consumption in the speaker 20 together with the DSP 14.

  Hereinafter, the current consumption measurement process in the speaker 20 by the DSP 14 and the microcomputer 22 will be described.

  FIG. 2 is a diagram illustrating the configuration of the DSP 14. 2 includes an attenuator (ATT) 52, an equalizer 54, a volume adjustment unit 56, a filter 58, a level correction unit 60, a sampling processing unit 62, a storage unit 64, and an average value calculation unit 66.

  The ATT 52 performs a process of attenuating the volume corresponding to the input digital audio signal with a predetermined attenuation, and outputs the digital audio signal corresponding to the attenuated volume to the equalizer 54. The equalizer 54 adjusts the frequency characteristic of the sound corresponding to the input digital audio signal and outputs the sound to the volume adjustment unit 56.

  The volume adjustment unit 56 adjusts the volume corresponding to the input digital audio signal according to the operation of the operation unit (not shown) by the user. Further, the volume adjustment unit 56 outputs a digital audio signal corresponding to the adjusted volume to the filter 58. The filter 58 is a digital filter, performs a filtering process on the input digital audio signal, and outputs it to the level correction unit 60. The level correction unit 60 corrects waveform shaping or the like for the input digital audio signal, and outputs it to the DAC 16 and the sampling processing unit 62.

  The sampling processing unit 62 samples the voltage level of the analog audio signal corresponding to the digital audio signal in a predetermined cycle with respect to the digital audio signal input as needed, and stores the voltage level data (sampling data). The data is stored in the unit 64. The average value calculation unit 66 reads sampling data within a predetermined period from the storage unit 64, calculates the average value (voltage average value), and stores the average value in the storage unit 64.

  Again, returning to FIG. The microcomputer 22 reads the voltage average value stored in the storage unit 64 in the DSP 14 and calculates the effective value (voltage effective value). Further, the microcomputer 22 estimates the current consumption value in the speaker 20 based on the voltage effective value.

  FIG. 3 is a diagram showing an outline of current consumption measurement processing in the speaker 20 by the DSP 14 and the microcomputer 22. The DSP 14 latches (holds) the input digital audio signal at a predetermined cycle, performs full-wave rectification on the analog audio signal corresponding to the digital audio signal in a predetermined period, and further performs processing corresponding to the integration processing. Then, the voltage average value of the analog audio signal in the predetermined period is calculated. On the other hand, the microcomputer 22 calculates a voltage effective value from the voltage average value, and estimates a current consumption value in the speaker 20 based on the voltage effective value.

  FIG. 4 is a flowchart showing the operation of the DSP 14 during current consumption measurement. As shown in FIG. 5, the storage unit 64 stores the number of sampling data (maximum number of sampling data) used for obtaining one voltage average value and the storage area of the storage unit 64 to which the sampling data is written. (Sampling Data Storage Area) Address (Write Address), Sampling Data Storage Area Address (Reading Address) of Storage Part 64 as Sampling Data Reading Source, and Storage Part as Voltage Average Value Storage Destination Information of addresses (voltage average value storage addresses) of 64 storage areas (voltage average value storage areas) is stored.

  Here, the maximum number of sampling data is set to a fixed value “15”. That is, one voltage average value is calculated from 15 sampling data. The write address has an initial value that is the maximum address in the sampling data storage area of the storage unit 64, and is decremented each time the sampling data is written to the sampling data storage area, and then the sampling data is written. Indicates the address of the sampling data storage area to be processed. The read address is the minimum address in the sampling data storage area of the storage unit 64, and is incremented every time the sampling data is written to the sampling data storage area, and then the sampling data is read out. Indicates the address of the storage area for the sampling data to be stored. A fixed value is set for the voltage average value storage address.

  The operation of the DSP 14 shown in FIG. 4 is performed in a state where the information as shown in FIG. 5 is stored in the storage unit 64. The sampling processing unit 62 in the DSP 14 acquires the write address stored in the storage unit 64 (S101). Next, the sampling processing unit 62 samples the voltage level of the analog audio signal corresponding to the digital audio signal in a predetermined cycle with respect to the digital audio signal output from the level correction unit 60, and the voltage level Sampling data which is the data of (2) is acquired (S102).

  Further, the sampling processing unit 62 stores the acquired one sampling data in the sampling data storage area of the storage unit 64 specified by the write address (S103). When the voltage level of the analog audio signal is a negative value, the sampling processing unit 62 stores the absolute value as sampling data in the sampling data storage area.

  Next, the sampling processing unit 62 decrements the write address stored in the sampling data storage area, and sets it as the address of the sampling data storage area where the sampling data is to be written next (S104).

  Further, the sampling processing unit 62 acquires the maximum number of samplings stored in the storage unit 64, and determines whether or not the sampling data storage process in S103 has been repeated 15 times corresponding to the maximum number of samplings (S105). .

  FIG. 6 is a diagram illustrating transition of the storage state of the sampling data in the sampling data storage area of the storage unit 64. The storage unit 64 is provided with 15 sampling data storage areas corresponding to the maximum number of samplings for storing sampling data. Sampling data is sequentially stored from the sampling data storage area of the maximum address, and when 15 sampling data are stored by the 15th storage process, the sampling data is stored in all the sampling data storage areas. Will be. In the 16th and subsequent storage processes, new sampling data is sequentially overwritten from the sampling data storage area of the maximum address where the sampling data is already stored.

  If the sampling data storage process in S103 has not been repeated 15 times, the operation after the acquisition of the write address (S101) is repeated. On the other hand, when the sampling data storage process in S103 is repeated 15 times, the process proceeds to the process by the average value calculation unit 66.

  That is, the average value calculation unit 66 acquires the read address stored in the storage unit 64 (S107). Next, the average value calculation unit 66 reads one sampling data from the sampling data storage area of the storage unit 64 specified by the read address (S108).

  Next, the average value calculation unit 66 adds the read sampling data to the calculation result (S109). The calculation result has an initial value of 0, and is a value that increases as sampling data is sequentially added. Furthermore, the average value calculation unit 66 increments the read address stored in the sampling data storage area, and sets it as the address of the sampling data storage area from which the sampling data is to be read next (S110).

  Further, the sampling processing unit 62 acquires the maximum number of samplings stored in the storage unit 64, and determines whether or not the sampling data addition processing in S109 has been repeated 15 times corresponding to the maximum number of samplings (S111). . Here, the addition of the sampling data in S109 being repeated 15 times means that the result of the arithmetic processing is the sum of 15 sampling data.

  If the sampling data calculation process in S109 has not been repeated 15 times, the operation after the acquisition of the read address (S107) is repeated. On the other hand, if the sampling data calculation process in S109 is repeated 15 times, in other words, if the result of the calculation process is a sum of 15 sampling data, the average value calculation unit 66 performs the calculation. The process result is multiplied by 1/15 to calculate a voltage average value (S112). For example, when the sampling period in S102 is 1/15 seconds, the voltage average value obtained by multiplying the result of the arithmetic processing obtained by adding 15 sampling data by 1/15 is the analog audio signal for 1 second. It represents the average value of.

  Further, the average value calculation unit 66 acquires the voltage average value storage address from the storage unit 64, and stores the calculated voltage average value in the storage area of the storage unit 64 specified by the voltage average value storage address (S113). ). Thereafter, the operations after the acquisition of the write address (S101) are repeated.

  FIG. 7 is a flowchart showing the operation of the microcomputer 22 during current consumption measurement. The operation shown in FIG. 7 is performed every time the DSP 14 stores the voltage average value in the storage area of the storage unit 64 specified by the voltage average value storage address.

  The microcomputer 22 acquires the voltage average value storage address stored in the storage unit 64 of the DSP 14 through SPI communication or I2C communication, and reads it from the storage area of the storage unit 64 specified by the voltage average value storage address (S201). ).

  Next, the microcomputer 22 performs a process of converting the read voltage average value into a voltage effective value (S202). Here, the microcomputer 22 assumes that the analog signal is a sine wave, and multiplies the voltage average value by 1.11 to obtain a voltage effective value. If the calculated voltage effective value is larger than the value (maximum effective value) obtained by multiplying the voltage of a battery (not shown) that supplies power to the speaker 20 by 0.707, the microcomputer 22 sets the effective voltage value to that value. Maximum effective value.

  Next, the microcomputer 22 calculates an estimated value of current consumption in the speaker 20 by dividing the calculated effective voltage value by the impedance value of the speaker 20 (S203).

  Further, the microcomputer 22 multiplies the estimated value of current consumption by a predetermined correction coefficient in accordance with the change in voltage by the DAC 16 and the AMP 18 existing between the DSP 14 and the speaker 20 (S204). Here, the correction coefficient is a value obtained in advance by actual measurement evaluation of the DAC 16 and the AMP 18.

  Next, the microcomputer 22 adds a predetermined current (idle current) of the speaker 20 when there is no digital audio signal to the multiplication value in S204, and determines the final current consumption value in the speaker 20. (S205).

  As described above, the in-vehicle audio apparatus 10-1 of the present embodiment can measure the current consumption in the speaker 20 by using the DSP 14 and the microcomputer 22 that are built in in advance for digital processing of signals. Become. Although the microcomputer 22 is slower in processing speed than the DSP 14, the DSP 14 calculates an average value of voltage levels of analog signals obtained by sampling within a predetermined period, and the microcomputer 22 calculates the analog signals. By calculating the effective value based on the average value of the voltage level and estimating the current consumption in the speaker 20, the difference in processing speed can be eliminated and the accurate measurement of the current consumption becomes possible. . Furthermore, unlike the prior art, measurement errors do not occur due to the accuracy of components such as an OP amplifier and an A / D converter used for current consumption measurement.

  Further, in the in-vehicle audio apparatus 10-1, the estimated value of the current consumption is multiplied by a predetermined correction coefficient according to a change in voltage by the DAC 16 and the AMP 18 existing between the DSP 14 and the speaker 20, and the speaker 20 Is added to the multiplication value to obtain a final current consumption value in the speaker 20, and a more accurate current consumption can be measured.

  In the above-described embodiment, the in-vehicle audio device 10-1 having one speaker 20 has been described, but the same applies to the in-vehicle audio device 10-2 having a plurality of speakers 20 as shown in FIG. The present invention can be applied. In this case, the DSP 14 and the microcomputer 22 can calculate the current consumption value for each speaker 20 and add them to measure the total current consumption. Further, when the impedance of each speaker 20 is the same, the DSP 14 and the microcomputer 22 calculate the current consumption value for one speaker 20 and multiply the value by the number of speakers 20 to obtain the overall consumption. Current can be measured.

  In the above-described embodiment, the case where the current consumption of the speaker 20 is measured has been described. However, the present invention can be similarly applied to the case where the current consumption of other analog elements is measured.

  As described above, the consumption current measuring apparatus according to the present invention can easily and accurately measure the consumption current in the analog elements in the circuit, and is useful as a consumption current measuring apparatus.

It is a figure which shows the structure of the vehicle-mounted audio apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of DSP. It is a figure which shows the outline | summary of the measurement process of the consumption current in the speaker by DSP and a microcomputer. It is a flowchart which shows the operation | movement at the time of the consumption current measurement of DSP. It is a figure which shows an example of information required for consumption current measurement. It is a figure which shows the transition of the storage state of sampling data. It is a flowchart which shows the operation | movement at the time of the consumption current measurement of a microcomputer. It is a figure which shows the other structure of the vehicle-mounted audio apparatus which concerns on embodiment of this invention.

Explanation of symbols

10-1, 10-2 On-vehicle audio system 12 Receiver 14 DSP
16 DAC
18 AMP
20 Speaker 22 Microcomputer 52 ATT
54 Equalizer 56 Volume Adjustment Unit 58 Filter 60 Level Correction Unit 62 Sampling Processing Unit 64 Storage Unit 66 Average Value Calculation Unit 200 Network

Claims (5)

A current consumption measuring device configured by a digital signal processor and a microcomputer built in a circuit and measuring current consumption in an analog element in the circuit,
The digital signal processor is:
Sampling means for sampling a digital signal representing a voltage level of an analog signal flowing through the circuit at a predetermined period;
Average value calculating means for calculating an average value of sampling data of the digital signal obtained by the sampling within a predetermined period;
The microcomputer has an effective value calculating means for calculating an effective value of a voltage level of the analog signal flowing through the circuit based on an average value of sampling data of the digital signal ;
A consumption current measuring device comprising: consumption current estimation means for estimating a consumption current value in the analog element based on an effective value of the voltage level of the analog signal. The digital signal processor is:
Storage means constituted by a number of storage areas corresponding to the number of sampling data of the digital signal obtained by sampling within the predetermined period;
The sampling means sequentially stores the sampling data of the digital signal obtained by the sampling in each of the areas,
2. The average value calculating unit reads sampling data of the digital signal obtained by the sampling from all storage areas constituting the storage unit at a cycle corresponding to the predetermined period. The current consumption measuring device described in 1. The average value calculating means performs a process corresponding to a process of full-wave rectifying and further integrating an analog signal represented by the digital signal with respect to sampling data of the digital signal obtained by sampling within the predetermined period. The consumption current measuring device according to claim 1, wherein the average value of the sampling data of the digital signal is calculated.   When there is another element between the sampling position of the sampling means and the analog element in the circuit, the microcomputer estimates the current consumption according to a change in voltage by the other element. 4. The consumption current measuring device according to claim 1, further comprising a correction unit that corrects a consumption current value of the analog element estimated by the unit.   5. The microcomputer according to claim 1, further comprising adding means for adding a predetermined idle current value to a current consumption value in the analog element estimated by the current consumption estimating means. Current consumption measuring device.

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